Apparently Amit Agarwal has reached the maximum amount of friendships allowed on Orkut and even provides a screenshot of the warning he received over on Digital Inspiration:
According to Amit this not only includes current friendships (regardless of level) but also open invitations as well.
You can have upto 1000 connections on Orkut. If you reach that limit, you will not be able to add new Orkut friends. This 1000 limit also includes Open Orkut Invitations - people you have invited to join Orkut but they haven't do so yet.
I have only 200 friends on Orkut [...] but when I tried adding adding a new friend, it says that before I can add new friends, I must remove old friends. [Hope this is not the case in real life]
I have heard rumors in the past of Orkut limiting friendship numbers to 1000, although there are users who have surpassed this amount, and have even created a forum called Tenho Mais de 1000 Friends (or I Have More than 1000 Friends) to celebrate this fact.
One user who goes by Gerente do orkut? reclamacoes aki has well over 10,000 friends and seems to be doing pretty well expanding his social network.
Perhaps these "mega friendship" users surpassed 1000 connections before Orkut imposed a limit system wide (and are thus grandfathered into the system). Either way it will be interesting to see if Orkut lifts or increases this in the future. If not, I would not be surprised if someone developed a hack around this.